It is generally recognised that unbalance of a grinding wheel can give rise to serious problems in regard to the operational performance thereof. In that connection it will be observed that unbalance of a grinding wheel primarily arises due to geometrical differences, an eccentric mounting for the grinding wheel, uneven abrasion of the grinding wheel in the course of use thereof, trimming and dressing of the grinding wheel, and differences in the absorption of coolant water as a result of the grinding wheel being of a non-homogeneous structure. When the grinding wheel rotates, such unbalance factors give rise to mass acceleration forces which have an effect on the structure of the grinding machine on which the grinding wheel is fitted. That in turn results in relative movements, caused by the unbalance of the grinding wheel, as between the workpiece being ground and the grinding wheel which is performing the grinding operation, and the relative movements can in turn result in the ground surfaces on the workpiece being machined suffering from surfaces rippling or even chatter marks. Balanced grinding wheels are therefore necessary in order to produce accurate surface profiles on the workpieces to be machined thereby.
For the purposes of balancing grinding wheels, two or three balancing weights in the form of slidable balancing weights may be arranged on the grinding wheel in a guide groove which extends around the axis of the grinding wheel, the balancing weights being disposed in dependence on the unbalance from which the grinding wheel is suffering. Reference may be made in that respect for example to Hofmann Informationen 12, special edition: Balancing of grinding wheels. In use of such an arrangement, the unbalance of the grinding wheel is measured by means of a measuring detector which is mounted on the grinding machine and to which an unbalance measuring device is connected. The unbalance measuring device is set to the speed of rotation of the grinding wheel so that essentially only oscillations which are at the same frequency as the rotating grinding wheel are displayed. The unbalance of the grinding wheel is then ascertained from the detected oscillations.
In effecting that procedure, the balancing weights have to be removed from the grinding wheel in order to measure the unbalance thereof, so as to ascertain the actual unbalance of the grinding wheel during the measuring operation. The balancing weights are then re-fitted to the grinding wheel, in dependence on the measured unbalance thereof. The operation of removing and refitting the balancing weights involves a relatively large amount of time and involves highly accurate operation in order the balancing weights to be secured to the grinding wheel in the correct positions thereon in order to compenstate for the grinding wheel unbalance.